I have an OctaMic XTC and was thinking of supplementing it with a Madiface Pro.  If I'm using a Mac Pro 2013, do I need to attach the Madiface Pro's included PSU to use a MADI I/O cable to/from the Octamic?  It isn't clear in the manual if this is required or not, but there is language that suggests the PSU connection is required, so I could use some clarification.  Thanks!